TECHNICAL FIELD
[0001] The present disclosure relates to the field of circuit protection, for example, a
surge protection circuit and an electronic device using the surge protection circuit.
BACKGROUND
[0002] An electronic device is often interfered with by an overvoltage. This overvoltage
includes an overvoltage generated by a lightning stroke and an overvoltage of a power
supply system. An overvoltage may damage the equipment. Thus, protective measures
must be taken to reduce the overvoltage to an acceptable level.
[0003] To protect the electronic device, a surge protection circuit may be used. FIG. 1
shows a surge protection circuit in the existing art. In this surge protection circuit,
a bidirectional thyristor surge suppressor (TSS) 102 is connected in series with a
unidirectional transient voltage suppressor (TVS) 104. The first end of the bidirectional
TSS is connected to the positive electrode of the power supply. The negative electrode
of the unidirectional TVS is connected to the second end of the bidirectional TSS.
The positive electrode of the unidirectional TVS is connected to the negative electrode
of the power supply. Thus, when the port of the power supply is impacted by a surge
from the positive electrode to the negative electrode, the bidirectional TSS and the
unidirectional TVS are conductive so that the surge current is shunted. Moreover,
the unidirectional TVS clamps the surge voltage between the two ends of the unidirectional
TVS to a clamping voltage. When the port of the power supply is impacted by a surge
from the negative electrode to the positive electrode, the bidirectional TSS and the
unidirectional TVS are conductive so that the surge current is shunted.
[0004] However, the preceding surge protection circuit has the disadvantage that the lightning
protection performance of the circuit varies significantly when the DC power port
is subjected to lightning strokes of different (positive or negative) polarities.
In the case of a lightning stroke from the negative electrode of the power supply
to the positive electrode of the power supply, the residual voltage between the two
ends of the surge protection circuit is high. When the circuit to be protected is
connected to the surge protection circuit for use, the current entering the circuit
to be protected is high and easily damages the circuit to be protected.
SUMMARY
[0005] In the present disclosure, a surge protection circuit is provided to solve the problem
where when a protection module in the existing art is subjected to a lightning stroke
from the negative electrode of the power supply to the positive electrode of the power
supply, the residual voltage between the two ends of the module is high, and the current
entering the protected circuit is high and easily damages the protected circuit.
[0006] A surge protection circuit includes: a bidirectional voltage suppressor; and a thyristor
surge suppression unit connected in parallel with the bidirectional voltage suppressor,
where a first end of the bidirectional voltage suppressor is connected to a first
end of the thyristor surge suppression unit, and a second end of the bidirectional
voltage suppressor is connected to a second end of the thyristor surge suppression
unit.
[0007] The breakover voltage or the breakdown voltage in the direction from the first end
of the thyristor surge suppression unit to the second end of the thyristor surge suppression
unit is greater than the clamping voltage in the direction from the first end of the
bidirectional voltage suppressor to the second end of the bidirectional voltage suppressor.
[0008] The breakover voltage in the direction from the second end of the thyristor surge
suppression unit to the first end of the thyristor surge suppression unit is less
than the clamping voltage in the direction from the second end of the bidirectional
voltage suppressor to the first end of the bidirectional voltage suppressor.
[0009] Optionally, the thyristor surge suppression unit is an asymmetric thyristor surge
suppression unit.
[0010] Optionally, the asymmetric thyristor surge suppression unit is a unidirectionally
conductive and reversely non-conductive thyristor surge suppressor.
[0011] Optionally, the asymmetric thyristor surge suppression unit is a bidirectional asymmetric
thyristor surge suppressor, and the breakover voltage in the direction from a first
end of the bidirectional asymmetric thyristor surge suppressor to a second end of
the bidirectional asymmetric thyristor surge suppressor is greater than the breakover
voltage in the direction from the second end of the bidirectional asymmetric thyristor
surge suppressor to the first end of the bidirectional asymmetric thyristor surge
suppressor.
[0012] Optionally, the asymmetric thyristor surge suppression unit includes a unidirectional
diode and a thyristor surge suppressor, and the bidirectional voltage suppressor is
connected in parallel with the unidirectional diode and the thyristor surge suppressor
which are connected in series. A cathode of the unidirectional diode is connected
to the first end of the bidirectional voltage suppressor, or an anode of the unidirectional
diode is connected to the second end of the bidirectional voltage suppressor.
[0013] Optionally, the bidirectional voltage suppressor is a bidirectional transient voltage
suppressor (TVS), a bidirectional asymmetric TVS, a voltage-dependent resistor, or
a bidirectional Zener diode.
[0014] Optionally, the clamping voltage in the direction from a first end of the bidirectional
asymmetric TVS to a second end of the bidirectional asymmetric TVS is less than the
clamping voltage in the direction from the second end of the bidirectional asymmetric
TVS to the first end of the bidirectional asymmetric TVS.
[0015] Optionally, the surge protection circuit further includes a tripping device. The
thyristor surge suppression unit is connected in parallel with the tripping device
and the bidirectional voltage suppressor which are connected in series, or the bidirectional
voltage suppressor is connected in parallel with the tripping device and the thyristor
surge suppression unit which are connected in series.
[0016] Optionally, the surge protection circuit further includes two tripping devices, which
comprise a first tripping device and a second tripping device. The first tripping
device and the bidirectional voltage suppressor are connected in series to form a
first branch, the second tripping device and the thyristor surge suppression unit
are connected in series to form a second branch, and the first branch is connected
in parallel with the second branch.
[0017] Optionally, the surge protection circuit further includes a unidirectional diode.
The thyristor surge suppression unit is connected in parallel with the unidirectional
diode and the bidirectional voltage suppressor which are connected in series. An anode
of the unidirectional diode is connected to the first end of the thyristor surge suppression
unit, or a cathode of the unidirectional diode is connected to the second end of the
thyristor surge suppression unit.
[0018] Further provided is an electronic device. The electronic device includes a main circuit
comprising an input end; and any surge protection circuit described above. In the
electronic device, the surge protection circuit is connected in parallel with the
main circuit and connected to the input end of the main circuit.
[0019] The surge protection circuit provided in the present disclosure can reduce the residual
voltage between the two ends of the surge protection circuit, and can further significantly
reduce the shunt of the subsequent circuit and improve the surge protection capability.
Thus, the surge protection circuit provided in the present disclosure can effectively
protect the electronic device from the surge current.
BRIEF DESCRIPTION OF DRAWINGS
[0020]
FIG. 1 is a schematic diagram of a surge protection circuit in the existing art;
FIG. 2 is a schematic diagram of a surge protection circuit according to an embodiment;
FIG. 3A is a schematic diagram of a surge protection circuit in which an asymmetric
thyristor surge suppression unit is a unidirectionally conductive and reversely non-conductive
TSS according to an embodiment;
FIG. 3B is a V-I curve of a unidirectionally conductive and reversely non-conductive
TSS according to an embodiment;
FIG. 3C is a schematic diagram of a surge protection circuit in which an asymmetric
thyristor surge suppression unit is a bidirectional asymmetric TSS according to an
embodiment;
FIG. 3D is a V-I curve of a bidirectional asymmetric TSS according to an embodiment;
FIG. 3E is a schematic diagram of an asymmetric thyristor surge suppression unit according
to another embodiment;
FIG. 4A is a schematic diagram of a surge protection circuit in which a bidirectional
voltage suppressor is a bidirectional TVS according to another embodiment;
FIG. 4B is a schematic diagram of a surge protection circuit in which a bidirectional
voltage suppressor is a bidirectional asymmetric TVS according to an embodiment;
FIG. 4C is a schematic diagram of a surge protection circuit in which a bidirectional
voltage suppressor is a voltage-dependent resistor according to an embodiment;
FIG. 4D is a schematic diagram of a surge protection circuit in which a bidirectional
voltage suppressor is a bidirectional voltage-regulator tube according to an embodiment;
FIG. 4E is a V-I curve of a bidirectional asymmetric TVS according to an embodiment;
FIG. 5A is a schematic diagram of a surge protection circuit including one tripping
device according to an embodiment;
FIG. 5B is a schematic diagram of a surge protection circuit including one tripping
device according to another embodiment;
FIG. 5C is a schematic diagram of a surge protection circuit including two tripping
devices according to an embodiment;
FIG. 6 is a schematic diagram of a surge protection circuit according to another embodiment;
and
FIG. 7 is a schematic diagram of an electronic device according to an embodiment.
DETAILED DESCRIPTION
[0021] As shown in FIG. 2, a surge protection circuit provided in the present embodiment
includes a bidirectional voltage suppressor 202 and a thyristor surge suppression
unit 208 connected in parallel with the bidirectional voltage suppressor 202. The
first end 204 of the bidirectional voltage suppressor 202 is connected to the first
end 210 of the thyristor surge suppression unit 208. The second end 206 of the bidirectional
voltage suppressor 202 is connected to the second end 212 of the thyristor surge suppression
unit 208. The breakover voltage or the breakdown voltage in the direction from the
first end 210 of the thyristor surge suppression unit 208 to the second end 212 of
the thyristor surge suppression unit 208 is greater than the clamping voltage in the
direction from the first end 204 of the bidirectional voltage suppressor to the second
end 206 of the bidirectional voltage suppressor. The breakover voltage in the direction
from the second end 212 of the thyristor surge suppression unit 208 to the first end
210 of the thyristor surge suppression unit 208 is less than the clamping voltage
in the direction from the second end 206 of the bidirectional voltage suppressor to
the first end 204 of the bidirectional voltage suppressor.
[0022] In the surge protection circuit provided in the present embodiment, the bidirectional
voltage suppressor is connected in parallel with the thyristor surge suppression unit.
The breakover voltage or the breakdown voltage in the direction from the first end
of the thyristor surge suppression unit to the second end of the thyristor surge suppression
unit is greater than the clamping voltage in the direction from the first end of the
bidirectional voltage suppressor to the second end of the bidirectional voltage suppressor,
and the breakover voltage in the direction from the second end of the thyristor surge
suppression unit to the first end of the thyristor surge suppression unit is less
than the clamping voltage in the direction from the second end of the bidirectional
voltage suppressor to the first end of the bidirectional voltage suppressor. When
the surge protection circuit is impacted by a surge from the first end of the bidirectional
voltage suppressor to the second end of the bidirectional voltage suppressor, the
bidirectional voltage suppressor is conductive to shunt the surge current, and the
surge voltage between the two ends of the bidirectional voltage suppressor is clamped
to the clamping voltage. When the surge protection circuit is impacted by a surge
from the second end of the thyristor surge suppression unit to the first end of the
thyristor surge suppression unit, the thyristor surge suppression unit is conductive
to shunt the surge current, and the surge voltage between the two ends of the thyristor
surge suppression unit is clamped to an on-state voltage. The preceding surge protection
circuit can reduce the residual voltage between the two ends of the surge protection
circuit, thereby significantly reducing the shunt of the subsequent circuit and improving
the surge protection capability. Thus, the surge protection circuit provided in the
present disclosure can effectively protect the electronic device from the surge current.
[0023] The thyristor surge suppression unit refers to a unit that integrally exhibits the
characteristics of the thyristor surge suppressor. The thyristor surge suppression
unit may be symmetrical or asymmetric as long as the breakover voltage or the breakdown
voltage in the direction from the first end of the thyristor surge suppression unit
to the second end of the thyristor surge suppression unit is greater than the clamping
voltage in the direction from the first end of the bidirectional voltage suppressor
to the second end of the bidirectional voltage suppressor and as long as the breakover
voltage in the direction from the second end of the thyristor surge suppression unit
to the first end of the thyristor surge suppression unit is less than the clamping
voltage in the direction from the second end of the bidirectional voltage suppressor
to the first end of the bidirectional voltage suppressor. Optionally, the thyristor
surge suppression unit is an asymmetric thyristor surge suppression unit. The asymmetric
thyristor surge suppression unit is a unit that integrally exhibits a characteristic
curve that satisfies the conditions described below.
[0024] The asymmetric thyristor surge suppression unit has a characteristic of reverse non-conductiveness
of an ordinary diode in the direction from its first end to its second end, and has
a characteristic of TSS in the direction from its second end to its first end. Alternatively,
the asymmetric thyristor surge suppression unit has the TSS-specific switching characteristic
in the two directions and has different electrical parameters in the two directions.
[0025] Optionally, as shown in FIG. 3A, the asymmetric thyristor surge suppression unit
is a unidirectionally conductive and reversely non-conductive thyristor surge suppressor
(TSS) 214. The unidirectionally conductive and reversely non-conductive TSS has a
characteristic of reverse non-conductiveness of an ordinary diode in the direction
from its first end 216 to its second end 218 and has the switching characteristic
of TSS in the direction from its second end 218 to its first end 216. The V-I curve
of the unidirectionally conductive and reversely non-conductive TSS is shown in FIG.
3B. The breakdown voltage Vz in the direction from the first end to the second end
of the unidirectionally conductive and reversely non-conductive TSS is greater than
the clamping voltage in the direction from the first end to the second end of the
bidirectional voltage suppressor. The breakover voltage Vs in the direction from the
second end to the first end of the unidirectionally conductive and reversely non-conductive
TSS is less than the clamping voltage in the direction from the second end to the
first end of the bidirectional voltage suppressor.
[0026] Optionally, as shown in FIG. 3C, the asymmetric thyristor surge suppression unit
is a bidirectional asymmetric thyristor surge suppressor (TSS) 220. The bidirectional
asymmetric TSS 220 has the TSS-specific switching characteristic in both the direction
from its first end to its second end and the direction from its second end to its
first end and has different electrical parameters in the two directions. For example,
the breakover voltage in the direction from its first end to its second end is greater
than the breakover voltage in the direction from its second end to its first end.
The V-I curve of the bidirectional asymmetric TSS 220 is shown in FIG. 3D. In FIG.
3D, Vdrm≠Vdrm*, Vs≠Vs*, Vt≠Vt*, It≠It*, Is≠Is*, Ih≠Ih*, and Idrm≠Idrm*. In this embodiment,
the breakover voltage Vs in the direction from the first end 222 of the bidirectional
asymmetric TSS 220 to the second end 224 of the bidirectional asymmetric TSS 220 is
greater than the breakover voltage Vs* in the direction from the second end 224 of
the bidirectional asymmetric TSS 220 to the first end 222 of the bidirectional asymmetric
TSS 220. The breakover voltage Vs in the direction from the first end of the bidirectional
asymmetric TSS to the second end of the bidirectional asymmetric TSS is greater than
the clamping voltage in the direction from the first end of the bidirectional voltage
suppressor to the second end of the bidirectional voltage suppressor. The breakover
voltage Vs in the direction from the second end of the bidirectional asymmetric TSS
to the first end of the bidirectional asymmetric TSS is less than the clamping voltage
in the direction from the second end of the bidirectional voltage suppressor to the
first end of the bidirectional voltage suppressor.
[0027] Optionally, the asymmetric thyristor surge suppression unit 208' includes a unidirectional
diode 404 and a thyristor surge suppressor 406. As shown in FIG. 3E, the bidirectional
voltage suppressor 202 is connected in parallel with the unidirectional diode 404
and the thyristor surge suppressor 406 which are connected in series, the cathode
of the unidirectional diode is connected to the first end 204 of the bidirectional
voltage suppressor 202, the anode of the unidirectional diode is connected to the
first end 408 of the thyristor surge suppressor 406, and the second end 410 of the
thyristor surge suppressor 406 is connected to the second end 206 of the bidirectional
voltage suppressor 202. The thyristor surge suppressor in FIG. 3E may be an ordinary
thyristor surge suppressor. In the direction from the cathode of the unidirectional
diode to the second end of the thyristor surge suppressor, the breakdown voltage formed
by the cathode of the unidirectional diode and the thyristor surge suppressor which
are in series connection is greater than the clamping voltage in the direction from
the first end of the bidirectional voltage suppressor to the second end of the bidirectional
voltage suppressor. In the direction from the second end of the thyristor surge suppressor
to the cathode of the unidirectional diode, the breakover voltage formed by the cathode
of the unidirectional diode and the thyristor surge suppressor which are in series
connection is less than the clamping voltage in the direction from the second end
of the bidirectional voltage suppressor to the first end of the bidirectional voltage
suppressor. Optionally, the thyristor surge suppressor herein may be a unidirectionally
conductive and reversely non-conductive thyristor surge suppressor or a bidirectional
asymmetric thyristor surge suppressor as mentioned above. The first end and the second
end of the thyristor surge suppressor respectively correspond to the first end and
the second end of the unidirectionally conductive and reversely non-conductive thyristor
surge suppressor, or the first end and the second end of the thyristor surge suppressor
respectively correspond to the first end and the second end of the bidirectional asymmetric
thyristor surge suppressor. In FIG. 3E, the position of the unidirectional diode is
not fixed. Optionally, the position of the unidirectional diode 404 may be interchanged
with the position of the thyristor surge suppressor 406. That is, the anode of the
unidirectional diode is connected to the second end of the bidirectional voltage suppressor,
the cathode of the unidirectional diode is connected to the second end of the thyristor
surge suppressor, and the first end of the thyristor surge suppressor is connected
to the first end of the bidirectional voltage suppressor.
[0028] Optionally, as shown in FIGS. 4A to 4D, the bidirectional voltage suppressor may
be a bidirectional TVS 302, a bidirectional asymmetric TVS 308, a voltage-dependent
resistor 314, or a bidirectional Zener diode 320. When the bidirectional voltage suppressor
is a bidirectional TVS 302, the first end 304 of the bidirectional TVS 302 is connected
to the first end 210 of the thyristor surge suppression unit 208, and the second end
306 of the bidirectional TVS 302 is connected to the second end 212 of the thyristor
surge suppression unit 208. When the bidirectional voltage suppressor is a bidirectional
asymmetric TVS 308, the first end 310 of the bidirectional asymmetric TVS 308 is connected
to the first end 210 of the thyristor surge suppression unit 208, and the second end
312 of the bidirectional asymmetric TVS 308 is connected to the second end 212 of
the thyristor surge suppression unit 208. When the bidirectional voltage suppressor
is a voltage-dependent resistor 314, the first end 316 of the voltage-dependent resistor
314 is connected to the first end 210 of the thyristor surge suppression unit 208,
and the second end 318 of the voltage-dependent resistor 314 is connected to the second
end 212 of the thyristor surge suppression unit 208. When the bidirectional voltage
suppressor is a bidirectional voltage-regulator tube 320, the first end 316 of the
bidirectional voltage-regulator tube 320 is connected to the first end 210 of the
thyristor surge suppression unit 208, and the second end 318 of the bidirectional
voltage-regulator tube 320 is connected to the second end 212 of the thyristor surge
suppression unit 208.
[0029] As described above, the thyristor surge suppression unit may be an asymmetric thyristor
surge suppression unit. The asymmetric thyristor surge suppression unit may be a unidirectionally
conductive and reversely non-conductive TSS, a bidirectional asymmetric TSS, or a
unit composed of a thyristor surge suppressor and a diode that are connected in series.
Thus, in this embodiment, the surge protection circuit may be formed of a first unit
and a second unit that are connected in parallel. The first unit is a bidirectional
TVS, a bidirectional asymmetric TVS, a voltage-dependent resistor, or a bidirectional
Zener diode. The second unit is a unidirectionally conductive and reversely non-conductive
TSS, a bidirectional asymmetric TSS, or a unit composed of a thyristor surge suppressor
and a diode that are connected in series.
[0030] Optionally, the bidirectional voltage suppressor may be a bidirectional asymmetric
TVS. The bidirectional asymmetric TVS has a clamping characteristic in both the direction
from its first end to its second end and the direction from its second end to its
first end. The asymmetry means that electrical parameters in the two directions are
different. For example, the clamping voltage in the direction from its first end to
its second end is greater than the clamping voltage in the direction from its second
end to its first end. The V-I curve of the bidirectional asymmetric TVS is shown in
FIG. 4E. In the figure 4E, Vc≠Vc*, Vbr≠VBR*, VDRM# VDRM*, IPP≠IPP*, IR≠IR*, and IDRM≠IDRM*.
Optionally, for the bidirectional asymmetric TVS, the clamping voltage Vc* in the
direction from its first end to its second end is less than the clamping voltage Vc
in the direction from its second end to its first end. In this embodiment, that Vc*
is less than Vc can reduce the residual voltage in the direction from the first end
to the second end of the bidirectional asymmetric TVS, thereby improving the performance
of the surge protection circuit.
[0031] Optionally, the surge protection circuit further includes a tripping device 402.
As shown in FIGS. 5A and 5B, the thyristor surge suppression unit 208 is connected
in parallel with the tripping device 402 and the bidirectional voltage suppressor
202 which are connected in series, or the bidirectional voltage suppressor 202 is
connected in parallel with the tripping device 402 and the thyristor surge suppression
unit 208 which are connected in series. The position of the tripping device 402 in
FIGS. 5A and 5B is not fixed. The position of the tripping device 402 in FIG. 5A may
be interchanged with the position of the bidirectional voltage suppressor. Likewise,
the position of the tripping device in FIG. 5B may be interchanged with the position
of the thyristor surge suppression unit.
[0032] Alternatively, the surge protection circuit includes two tripping devices 402, which
are a first tripping device and a second tripping device. The first tripping device
and the bidirectional voltage suppressor 202 are connected in series to form a first
branch. The second tripping device and the thyristor surge suppression unit are connected
in series to form a second branch. The first branch is connected in parallel with
the second branch. See FIG. 5C. Likewise, the positions of the tripping devices in
the figure are not fixed and may be interchanged with the position of the bidirectional
voltage suppressor or the position of the thyristor surge suppression unit.
[0033] The addition of a tripping device ensures the safety of the surge protection circuit.
Under an extreme condition of the circuit, for example, under the condition of the
circuit heating caused by an overhigh current, the tripping device 402 may cut off
the branch where the tripping device 402 is located to avoid an accident like circuit
burnout.
[0034] Optionally, the surge protection circuit may further include a unidirectional diode
404. As shown in FIG. 6, the thyristor surge suppression unit 208 is connected in
parallel with the unidirectional diode 404 and the bidirectional voltage suppressor
202 which are connected in series, the anode of the unidirectional diode 404 is connected
to the first end 210 of the thyristor surge suppression unit 208, the cathode of the
unidirectional diode is connected to the first end 204 of the bidirectional voltage
suppressor 202, and the second end 206 of the bidirectional voltage suppressor 202
is connected to the second end 212 of the thyristor surge suppression unit 208. The
position of the unidirectional diode in FIG. 7 is not fixed. Optionally, the position
of the unidirectional diode 404 may be interchanged with the position of the bidirectional
voltage suppressor. That is, the cathode of the unidirectional diode is connected
to the second end of the thyristor surge suppression unit, the anode of the unidirectional
diode is connected to the second end of the bidirectional voltage suppressor, and
the first end of the bidirectional voltage suppressor is connected to the first end
of the thyristor surge suppression unit.
[0035] The addition of a diode to the circuit further ensures that when a surge flows from
the second end of the thyristor surge suppression unit to the first end of the thyristor
surge suppression unit, the surge current is discharged through the thyristor surge
suppression unit and does not pass through the bidirectional voltage suppressor.
[0036] As shown in FIG. 7, an electronic device is provided in this embodiment. The electronic
device includes a main circuit 412 and the preceding surge protection circuit. The
main circuit 412 has input ends 414. The surge protection circuit is connected in
parallel with the main circuit and connected to the input end 412 of the main circuit.
The surge protection circuit is disposed before the main circuit 412 to protect the
main circuit from a surge, so that the electronic device has a good surge protection
capability.
INDUSTRIAL APPLICABILITY
[0037] The surge protection circuit provided in the present disclosure can reduce the residual
voltage between the two ends of the protection module, significantly reduce the shunt
of the subsequent circuit, improve the surge protection capability, and better protect
an electronic device from the surge current.
1. A surge protection circuit comprising:
a bidirectional voltage suppressor; and
a thyristor surge suppression unit connected in parallel with the bidirectional voltage
suppressor, wherein a first end of the bidirectional voltage suppressor is connected
to a first end of the thyristor surge suppression unit, and a second end of the bidirectional
voltage suppressor is connected to a second end of the thyristor surge suppression
unit,
wherein a breakover voltage or a breakdown voltage in a direction from the first end
of the thyristor surge suppression unit to the second end of the thyristor surge suppression
unit is greater than a clamping voltage in a direction from the first end of the bidirectional
voltage suppressor to the second end of the bidirectional voltage suppressor; and
wherein a breakover voltage in a direction from the second end of the thyristor surge
suppression unit to the first end of the thyristor surge suppression unit is less
than a clamping voltage in a direction from the second end of the bidirectional voltage
suppressor to the first end of the bidirectional voltage suppressor.
2. The surge protection circuit of claim 1, wherein the thyristor surge suppression unit
is an asymmetric thyristor surge suppression unit.
3. The surge protection circuit of claim 2, wherein the asymmetric thyristor surge suppression
unit is a unidirectionally conductive and reversely non-conductive thyristor surge
suppressor.
4. The surge protection circuit of claim 2, wherein the asymmetric thyristor surge suppression
unit is a bidirectional asymmetric thyristor surge suppressor, and a breakover voltage
in a direction from a first end of the bidirectional asymmetric thyristor surge suppressor
to a second end of the bidirectional asymmetric thyristor surge suppressor is greater
than a breakover voltage in a direction from the second end of the bidirectional asymmetric
thyristor surge suppressor to the first end of the bidirectional asymmetric thyristor
surge suppressor.
5. The surge protection circuit of claim 2, wherein the asymmetric thyristor surge suppression
unit comprises a unidirectional diode and a thyristor surge suppressor, and the bidirectional
voltage suppressor is connected in parallel with the unidirectional diode and the
thyristor surge suppressor which are connected in series, wherein a cathode of the
unidirectional diode is connected to a first end of the bidirectional voltage suppressor,
or an anode of the unidirectional diode is connected to a second end of the bidirectional
voltage suppressor.
6. The surge protection circuit of claim 1, wherein the bidirectional voltage suppressor
is a bidirectional transient voltage suppressor (TVS), a bidirectional asymmetric
TVS, a voltage-dependent resistor, or a bidirectional Zener diode.
7. The surge protection circuit of claim 6, wherein a clamping voltage in a direction
from a first end of the bidirectional asymmetric TVS to a second end of the bidirectional
asymmetric TVS is less than a clamping voltage in a direction from the second end
of the bidirectional asymmetric TVS to the first end of the bidirectional asymmetric
TVS.
8. The surge protection circuit of any one of claims 1 to 7, further comprising a tripping
device,
wherein the thyristor surge suppression unit is connected in parallel to the tripping
device and the bidirectional voltage suppressor which are connected in series, or
the bidirectional voltage suppressor is connected in parallel to the tripping device
and the thyristor surge suppression unit which are connected in series.
9. The surge protection circuit of any one of claims 1 to 7, further comprising two tripping
devices, which comprise a first tripping device and a second tripping device,
wherein the first tripping device and the bidirectional voltage suppressor are connected
in series to form a first branch, the second tripping device and the thyristor surge
suppression unit are connected in series to form a second branch, and the first branch
is connected in parallel with the second branch.
10. The surge protection circuit of claim 1, further comprising a unidirectional diode,
wherein the thyristor surge suppression unit is connected in parallel to the unidirectional
diode and the bidirectional voltage suppressor which are connected in series,
wherein an anode of the unidirectional diode is connected to the first end of the
thyristor surge suppression unit, or a cathode of the unidirectional diode is connected
to the second end of the thyristor surge suppression unit.
11. An electronic device, comprising:
a main circuit comprising an input end; and
the surge protection circuit of any one of claims 1 to 10, wherein the surge protection
circuit is connected in parallel with the main circuit and connected to the input
end of the main circuit.